Archeologist Frank Hibben writes of an actual climate-change that took place long before SUVs and hockey-sticks.

" In many places the Alaskan muck is packed with animal bones and debris in trainload lots. Bones of mammoth, mastodon, several kinds of bison, horses, wolves, bears, and lions tell a story of a faunal population.

" The Alaskan muck is like a fine, dark gray sand. Within this mass, frozen solid, lie the twisted parts of animals and trees intermingled with lenses of ice and layers of peat and mosses. It looks as though in the midst of some cataclysmic catastrophe of ten thousand years ago the whole Alaskan world of living animals and plants was suddenly frozen in midmotion in a grim charade.

" Throughout the Yukon and its tributaries, the gnawing currents of the river had eaten into many a frozen bank of muck to reveal bones and tusks of these animals protruding at all levels. Whole gravel bars in the muddy river were formed of the jumbled fragments of animal remains.

" The Pleistocene period ended in death. This is no ordinary extinction of a vague geological period which fizzled to an uncertain end. This death was catastrophic and all-inclusive. The large animals that had given their name to the period became extinct. Their death marked the end of an era."

I'll be 85 in two weeks and I first read this book in my high school's excellent library, where I worked once a week. It was written in 1946 so obviously it's quite dated both informationally and culturally, but it you are as interested in paleontology and archaeology as I've been since childhood, you will recognize the ideas that have changed because of numerous discoveries. It was written for an audience that is generally educated but unfamiliar with the archaeology of the ancient US. Dr Hibben was a professor of archaeology at the Univ. of New Mexico, an on-site digger, and was professionally well equipped to write a book like this, which also exudes with his enthusiasm for his career. Beware the racism in some of his references to modern Indians, which is why I can't give it the highest rating, but it's a fine introduction to the 1940s understanding of early North America. Read it alongside Charles Mann's 1491, for an up-to-date and anti-racist portrait of the accomplishments of the Pre-Columbian Indians.